What is a trough line? A trough is an elongated (extended) region of relatively low atmospheric pressure, often associated with fronts. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked as a dashed line or bold line. Click to see full answer.
What is a trough?
A trough is an elongated (extended) region of relatively low atmospheric pressure, often associated with fronts. Troughs may be at the surface, or aloft, or both under various conditions.
What is a trough in the westerlies?
For a trough in the westerlies, the region just west of the trough axis is typically an area of convergent winds and descending air – and hence high pressure –, while the region just east of the trough axis is an area of fast, divergent winds and low pressure. Tropical waves are a type of trough in easterly currents,...
What is the difference between a trough and boundary?
Description. A trough is not in a general term a boundary but an elongated area of lower air pressure. There are changes in wind direction across a trough but there is no change in air mass. While not specifically a surface boundary, troughs reflect the change in atmospheric conditions in the upper atmosphere.
What is the difference between a col and a trough?
In the absence of a wind shift, the region is designated a col, akin to a geographic saddle between two mountain peaks. A trough is the result of the movements of the air in the atmosphere. In regions where there is upward movement near the ground and divergence at altitude, there is a loss of mass. The pressure becomes lower at this point.
What is the difference between a trough and a front?
Troughs. A trough appears on the weather map as a dashed blue line on the chart. It is an elongated area where atmospheric pressure is low relative to its immediate surroundings. Like cold fronts, troughs separate two different air masses (usually more moist air on one side and drier air on the other).
How do you identify a trough?
Open Waves Low-pressure troughs are identified by brown dashed lines while ridges of high pressure are identified by brown zigzag lines. The majority of inclement weather occurs between the trough and the downwind (eastward) ridge while fair weather occurs between the ridge and the downwind trough.
What does a trough look like?
Troughs and ridges look like what you might expect; a trough is roughly U shaped. To the east of the trough, air will usually rise, allowing for the development of precipitation.
How do troughs affect weather?
Troughs have the potential to intensify rapidly, generally at the expense of the cold front, resulting in strengthening of the northerly winds ahead of a cool change. In summer the major significant wind change is associated with prefrontal troughs.
What is a trough in a graph?
The opposite of peak in a graph – the lowest part of the line on a graph, between where it falls and rises.
How is a trough formed?
Formation. A trough is the result of the movements of the air in the atmosphere. In regions where there is upward movement near the ground and divergence at altitude, there is a loss of mass. The pressure becomes lower at this point.
What's the difference between a trough and ridge?
Ridges and troughs are often mentioned on the weather forecast. A ridge is an elongated area of relatively high pressure extending from the center of a high-pressure region. A trough is an elongated area of relatively low pressure extending from the center of a region of low pressure.
What are peaks and troughs?
Peaks and troughs are the highest and lowest concentrations, respectively, of a medication in an individual's body. They are used to determine dosing intervals, especially during therapeutic drug monitoring.
What is monsoon trough line?
The monsoon trough is a portion of the Intertropical Convergence Zone in the Western Pacific, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and northern hemispheres.
What happens during a trough?
Key Takeaways A trough, in economic terms, can refer to a stage in the business cycle where activity is bottoming, or where prices are bottoming, before a rise. The business cycle is the upward and downward movement of gross domestic product (GDP) and consists of recessions and expansions that end in peaks and troughs.
What is a trough in the ocean?
oceanic trough, an elongate depression in the seafloor that is characteristically shallower, shorter, narrower, and topographically gentler than oceanic trenches.
What is a thermal trough?
A thermal trough is a region of synoptic scale cooler temperatures while a thermal ridge is a region of synoptic scale warmer temperatures. The word thermal is a descriptor of temperature, trough a descriptor of "lower values", and ridge a descriptor of "higher values".
What are troughs in the jet stream?
Near-surface troughs sometimes mark a weather front associated with clouds, showers, and a wind direction shift. Upper-level troughs in the jet stream (as shown in diagram) reflect cyclonic filaments of vorticity. Their motion induces upper-level wind divergence, lifting and cooling the air ahead (downstream) of the trough and helping to produce cloudy and rain conditions there.
What is the building phase of a trough?
A trough will usually begin with a positive tilt as cold air moves toward the Equator. The trough will become neutral (North-South) and then negatively tilted as the energy carried by the cold air races east though the atmospheric circulation and distorts its shape. The positive tilt is thus the building phase of the trough and the negative tilt is the dissipation of its energy. Therefore, the clouds and precipitation will develop in the positive phase and the most severe weather will be in the negative phase.
What is an inverted trough?
An inverted trough is an atmospheric trough which is oriented opposite to most troughs of the mid-latitudes. Most (but not all) inverted troughs are tropical waves (also commonly called easterly waves).
What is a trough in the hemisphere?
A trough is an elongated region of relatively low atmospheric pressure without a closed isobaric contour that would define it as a low pressure area. ...
What is a trough on a weather chart?
The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked as a dashed line or bold line. In the UK, Hong Kong and Fiji, it is represented by a bold line extended from a low pressure center or between two low pressure centers; in Macau and Australia, it is a dashed line. If they are not marked, troughs may still be identified as an extension of isobars away from a low pressure center .
What is the difference between a trough and a tropical wave?
For a trough in the westerlies, the region just west of the trough axis is typically an area of convergent winds and descending air – and hence high pressure –, while the region just east of the trough axis is an area of fast, divergent winds and low pressure. Tropical waves are a type of trough in easterly currents, ...
What is a trough?
A trough is an elongated region of relatively low atmospheric pressure without a closed isobaric contour that would define it as a low pressure area. Since low pressure implies a low height on a pressure surface, troughs and ridges refer to features in an identical sense as those on a topographic map. Troughs may be at the surface, or aloft.
Why are troughs and ridges important?
Troughs and ridges are important features in predicting the weather. They can tell you whether rain or snow is on the way or if dry conditions are likely. So, pay attention next time the weather comes because knowing where you are in regards to a trough or ridge will help you understand your weather forecast.
What do troughs and ridges look like?
Have you ever wondered what they are and why they are important? Troughs and ridges look like what you might expect; a trough is roughly U shaped. To the east of the trough, air will usually rise, allowing for the development of precipitation.
What is the weather like under a ridge?
If you’re under a ridge during the summer, conditions are usually hot and dry . In the Northern Hemisphere, winds will blow clockwise around a high (northwesterly northwest of the ridge and southwesterly southwest of the ridge. Broadly speaking, troughs and ridges are properties of the pressure field and they can easily be seen on a weather map.
Overview
A trough is an elongated region of relatively low atmospheric pressure without a closed isobaric contour that would define it as a low pressure area. Since low pressure implies a low height on a pressure surface, troughs and ridges refer to features in an identical sense as those on a topographic map.
Troughs may be at the surface, or aloft. Near-surface troughs sometimes mar…
Description
A trough is an elongated area of lower air pressure. Since pressure is closely linked to wind, there are often changes in wind direction across a trough.
If a trough forms in the mid-latitudes, a temperature difference at some distance between the two sides of the trough usually exists and the trough might become a weather front at some point. However, such a weather front is usually less convective than a trough in the tropics or subtropi…
Formation
A trough is the result of the movements of the air in the atmosphere. In regions where there is upward movement near the ground and divergence at altitude, there is a loss of mass. The pressure becomes lower at this point.
At upper levels of the atmosphere, this occurs when there is a meeting of a mass of cold air and another hot one along a thin ribbon called a frontal baroclinic zone. We then have the creation of a jet …
Types of trough
In addition to standard troughs, some troughs may be described further with a qualifying term indicating a specific or a set of characteristics.
An inverted trough is an atmospheric trough which is oriented opposite to most troughs of the mid-latitudes. Most (but not all) inverted troughs are tropical waves (also commonly called easterly waves).
Weather associated
Convective cells may develop in the vicinity of troughs and give birth to a tropical cyclone. Some tropical or subtropical regions such as the Philippines or south China are greatly affected by convection cells along a trough.
In the mid-latitude westerlies, upper level troughs and ridges often alternate in a high-amplitude pattern. For a trough in the westerlies, the region just west of the trough axis is typically an area …
See also
• Asiatic low
• Geopotential height
• Surface weather analysis